The present technology relates to a semiconductor module. More particularly, the present technology relates to a semiconductor module in which data signal lines and strobe signal lines are wired.
In the related art, various types of semiconductor packages are used for the purpose of protecting a chip and the like in a semiconductor module. As type of semiconductor package, a Quad Flat Package (QFP) in which rectangular lead terminals protrude at four sides, a Ball Grid Array (BGA) package in which ball terminals of a ball shape are arrayed in a grid shape on a surface, and the like are known. Here, in general, the ball terminal is smaller than the lead terminal, and a density of the ball terminal can be set to be higher than that of the lead terminal. Therefore, the BGA package is often used when intending to reduce a mounting area.
When providing a memory chip such as a Double Data Rate Synchronous DRAM (DDR SDRAM) and the like, and a chip of a memory controller in the BGA package, data signal lines and strobe signal lines are wired between these chips. The data signal line is a signal line which transfers a data signal. The strobe signal line is a signal line which indicates a timing to capture the data signal at a receiving side and transfers a strobe signal. In the BGA package, when wiring all of the data signal lines and the strobe signal lines on a surface on which chips are disposed, the chips have to be disposed on the same surface. Thus, wiring becomes difficult as the number of data signal lines and the like is increased. Accordingly, the BGA package which wires the data signal lines and the strobe signal lines on a lower layer through vias passing through an upper layer by using a substrate of a plurality of layers as a substrate for a semiconductor package, and by disposing chips on these upper layers has been proposed (for example, refer to Japanese Patent No. 4662474).